The invention relates in general to munitions and in particular to submunitions and cluster munitions.
Cluster bombs may be dispensed from dispensers and dropped in a pattern to blanket a target area. This method may be used to increase the probability that an individual submunition will encounter, engage, and destroy targets within the target area. Submunitions may be ejected in a dispersion pattern that may depend on the nature of the ejection mechanism used in the submunition carrier. Submunitions may be armed as they are dispensed from the cluster bomb or other carrier. If the submunitions do not encounter and engage a target, they may remain unexploded, armed, and lethal when they impact the ground and after impact with the ground.
This overall approach to engaging one or more targets with many individual munitions or dispensed submunitions is often referred to as an “area attack” and is a statistical methodology for defeating targets. Area attack may be contrasted with “precision attack,” which typically uses one precision-guided munition to engage each target individually. Assuming an accurate target location, precision attack may yield a higher percentage of kills per munition, but at a substantially higher cost due to the use of precision guidance and control on each munition.
Submunitions of various kinds may be ejected or dispersed from a carrier, such as a missile, mortar, rocket or cannon projectile. Generally, the carrier brings the submunitions to a location close to the target, and the submunitions are then ejected or dispersed near the target. The submunitions may free fall from the ejection location and rely on statistical distribution to hit the target, or the submunitions may include a guidance system to move them closer to the target. A number of methods are known for guiding the submunitions to the final target.
One method employs terminal guidance systems, such as infrared seekers and other IR detection and guidance systems, as shown, for example, in U.S. Pat. No. 4,492,166. Another method provides mechanical control systems, such as aerofoils or special wings with a target detector, such as those shown in U.S. Pat. No. 5,155,294 and U.S. Pat. No. 4,635,553. In U.S. Pat. No. 4,554,871, assigned to Allied Corporation, there is disclosed a missile that carries at least two asymmetric submunitions. The guidance system on each submunition causes the submunition to precess about its center axis, thereby creating an appropriate search pattern or controlling the flight path of the submunition after a suitable target has been acquired by the submunition's guidance system.
Satellite aided global location systems, such as the Global Positioning System (GPS), are also well known in the art. These systems utilize several satellites to permit a body on the earth to calculate, such as by triangulation, its precise location on the globe. Global location systems today are used in guidance systems for a wide variety of objects. These include munitions, such as bombs and missiles. There is shown, for instance, in U.S. Pat. No. 5,943,009, assigned to Northrop Grumman Corporation, a munition with a tail fin assembly, at least one flight control surface having an actuator, and a guidance system having a GPS receiver for effecting control of the actuator to facilitate guiding of the munition.
U.S. Pat. No. 5,260,709 discloses a system and method that uses differential computation of position relative to a GPS coordinate system and the computation of an optimum weapon flight path to guide a weapon to a non-moving fixed or re-locatable target. The system comprises an airborne platform with a navigation subsystem that utilizes the GPS satellite system to provide the coordinate system, and a synthetic array radar (SAR) to locate desirable targets. Targeting is done prior to weapon launch; therefore, the weapon requires only a navigation subsystem that also utilizes the GPS satellite system to provide the same coordinate system that the platform uses.
There is shown in U.S. Pat. No. 5,507,452 a precision guided system suitable for use in conventional aircraft-launched bombs. The system includes a kit mounted upon the nose of the conventional bomb which replaces the conventional fuse disposed in a fuse well. The kit includes guidance electronics that control a self-contained jet reaction device and GPS P-code receiver electronics. The bombs are readied for discharge by signals broadcast from the aircraft into the bomb bay. Readying the bombs includes transferring initial GPS data and commencing operation of a gas generator which powers the jet reaction device.
There is shown in U.S. Pat. No. 6,481,666 a method and system for guiding submunitions in which a satellite-aided global location system is utilized to control a parachute disposed on each submunition. In particular, the orientation of the parachute is adjusted by a servo, which in turn is controlled by the guidance system, thus allowing alteration in direction of downward travel of the submunition. U.S. Pat. Appl. Publication No. 2007/0266884 discloses a dispenser system for controllably deploying components, such as unmanned ground sensors, into a desired pattern and orientation. The dispenser system utilizes a GPS-based guidance system to control the deployment of the main canister, rather than the submunitions.
All of the above-mentioned systems include the use of satellite-aided global location systems to guide a munition over a relatively long distance and/or control a relatively complex guidance system (to control, for example, the orientation of fins, parachutes, etc.). Thus, the electronics and control system required to guide the munitions are complex and expensive to manufacture and maintain. Further, the submunitions themselves are incapable of communicating with one another so as provide selective targeting. Moreover, deployment of conventional cluster munitions results in relatively high incidences of unexploded ordinance.
The Oslo Treaty dated May 30, 2008 requires that all cluster munitions weighing less than 20 kg contain less than 10 submunitions. Each submunition must be single target discriminating, must weigh more than 4 kg, and must have an electronic self-destruct and self-deactivate capability. The conventional cluster munitions described above do not meet the Oslo Treaty requirements. A need exists for a cluster munition and submunitions that meet the Oslo Treaty requirements, while also providing effective targeting and enemy elimination characteristics.